I think this is the hardest puzzle in the entire game.

Looking at the bottom of the oyster gives you a clue that there is one word that works differently in this room. The word is "blast." Before now, it would give you a message that "I see no dynamite here." But now it causes the rod in this room to explode!

Don't explode the rod while you are in the same corner of the repository with it, for obvious reasons. (Try it. Be sure to save your game first, though.)

You need to put the rod in one corner of the repository, go to the opposite corner, and blast. Which is the correct corner? Well, go find out. You have a 50% chance if you guess. (Yes, I know, but why tell you when it's easy to find out for yourself?)

Once you solve this one remaining problem, the game will end with a congratulatory message, you will get your final score, and then finally you can once get on with your life.